Evaluation of Different Soil Carbon Determination Methods

Abstract Determining soil carbon (C) with high precision is an essential requisite for the success of the terrestrial C sequestration program. The informed choice of management practices for different terrestrial ecosystems rests upon accurately measuring the potential for C sequestration. Numerous methods are available for assessing soil C. Chemical analysis of field-collected samples using a dry combustion method is regarded as the standard method. However, conventional sampling of soil and their subsequent chemical analysis is expensive and time consuming. Furthermore, these methods are not sufficiently sensitive to identify small changes over time in response to alterations in management practices or changes in land use. Presently, several different in situ analytic methods are being developed purportedly offering increased accuracy, precision and cost-effectiveness over traditional ex situ methods. We consider that, at this stage, a comparative discussion of different soil C determination methods will improve the understanding needed to develop a standard protocol. Keywords: soil carbonwet oxidationdry combustioninelastic neutron scatteringremote sensinglaser induced breakdown spectroscopy ACKNOWLEDGMENTS This papar is also referenced as Los Alamos National Laboratory unclassified report LA-UR-08-05870. Some or all LIBS applications described in this paper are protected by U.S. Patent Application held by Los Alamos National Loboratory. Referee: Dr. John M. Kimble, USDA-NRCS (Ret.), 151 East Hill Church Road, Addison, NY 14801